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- Genetic variation (4)
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Articles 1 - 14 of 14
Full-Text Articles in Life Sciences
Two Hundred Years Of Forest Change: Effects Of Urbanization On Tree Species Composition And Structure, Rebecca W. Dolan
Two Hundred Years Of Forest Change: Effects Of Urbanization On Tree Species Composition And Structure, Rebecca W. Dolan
Scholarship and Professional Work - LAS
Despite their importance, the dynamics of urban floras are not well understood and quantitative historical data are rare. The current study used three data sets for trees in Indianapolis/Marion County, Indiana, U.S., to document change over 200 years to the original beech-maple forest and to examine future implications of contemporary tree planting efforts in light of these changes. Data on tree composition and size collected before significant settlement in the early 1800s are compared with recent surveys of trees in remnant natural areas and with trees found on city streets and rights-of-way. All the species recorded in historical surveys are …
Changes In Plant Species Composition And Structure In Two Peri-Urban Nature Preserves Over 10 Years, Rebecca W. Dolan, Jessica D. Stepens, Marcia E. Moore
Changes In Plant Species Composition And Structure In Two Peri-Urban Nature Preserves Over 10 Years, Rebecca W. Dolan, Jessica D. Stepens, Marcia E. Moore
Scholarship and Professional Work - LAS
Peri-urban natural areas, at the boundaries of cities and adjacent agricultural/rural land, are subject to ecological threats endemic to both land use types. We used permanent plots to document changes in habitat quality by monitoring herbaceous-layer plant species presence and cover over a decade (1996/97 and 2007) in two peri-urban nature preserves in central Indiana, U.S.A. The preserves are comprised of different forest community types: wet-mesic depressional forest and mesic upland forest. Habitat characteristics, based on Floristic Quality Assessment parameters, showed only a single change for either preserve between survey years: wetness values were lower in the wet-mesic depressional site …
Soil C And N Changes With Afforestation Of Grasslands Across Gradients Of Precipitation And Plantation Age, Sean T. Berthrong, Gervasio Pinero, Esteban G. Jobbagy, Robert B. Jackson
Soil C And N Changes With Afforestation Of Grasslands Across Gradients Of Precipitation And Plantation Age, Sean T. Berthrong, Gervasio Pinero, Esteban G. Jobbagy, Robert B. Jackson
Scholarship and Professional Work - LAS
Afforestation, the conversion of unforested lands to forests, is a tool for sequestering anthropogenic carbon dioxide into plant biomass. However, in addition to altering biomass, afforestation can have substantial effects on soil organic carbon (SOC) pools, some of which have much longer turnover times than plant biomass. An increasing body of evidence suggests that the effect of afforestation on SOC may depend on mean annual precipitation (MAP). The goal of this study was to test how labile and bulk pools of SOC and total soil nitrogen (TN) change with afforestation across a rainfall gradient of 600–1500 mm in the Rio …
Genetic Variation In Past And Current Landscapes: Conservation Implications Based On Six Endemic Florida Scrub Plants, Eric S. Menges, Rebecca W. Dolan, Robert Pickert, Rebecca Yahr, Doria R. Gordon
Genetic Variation In Past And Current Landscapes: Conservation Implications Based On Six Endemic Florida Scrub Plants, Eric S. Menges, Rebecca W. Dolan, Robert Pickert, Rebecca Yahr, Doria R. Gordon
Scholarship and Professional Work - LAS
If genetic variation is often positively correlated with population sizes and the presence of nearby populations and suitable habitats, landscape proxies could inform conservation decisions without genetic analyses. For six Florida scrub endemic plants (Dicerandra frutescens, Eryngium cuneifolium, Hypericum cumulicola, Liatris ohlingerae, Nolina brittoniana, and Warea carteri), we relate two measures of genetic variation, expected heterozygosity and alleles per polymorphic locus (APL), to population size and landscape variables. Presettlement areas were estimated based on soil preferences and GIS soils maps. Four species showed no genetic patterns related to population or landscape factors. The …
Capturing Genetic Variation During Ecological Restorations: An Example From Kankakee Sands In Indiana, Rebecca W. Dolan, Deborah L. Marr, Andrew Schnabel
Capturing Genetic Variation During Ecological Restorations: An Example From Kankakee Sands In Indiana, Rebecca W. Dolan, Deborah L. Marr, Andrew Schnabel
Scholarship and Professional Work - LAS
Genetic variation in populations, both natural and restored, is usually considered crucial for response to short term environmental stresses and for long term evolutionary change. To have the best chance of successful long-term survival, restored populations should reflect the extant variation found in remnants, but restored sites may suffer from genetic bottlenecks as a result of founder effects. Kankakee Sands is a large-scale restoration being conducted by The Nature Conservancy (TNC) in northwestern Indiana. Our goal was to test for loss of genetic variation in restored plant populations by comparing them with TNC’s seed source nursery and with local remnant …
Population Genetic Structure In Nolina Brittoniana (Agavaceae), A Plant Endemic To The Central Ridges Of Florida, Rebecca W. Dolan, Rebecca Yahr, Eric S. Menges
Population Genetic Structure In Nolina Brittoniana (Agavaceae), A Plant Endemic To The Central Ridges Of Florida, Rebecca W. Dolan, Rebecca Yahr, Eric S. Menges
Scholarship and Professional Work - LAS
Nolina brittoniana is endemic to the central ridges of peninsular Florida. Its scrub and sandhill habitats have suffered extensive anthropogenic modification. Analysis of isozymes from populations throughout its range revealed less genetic variation than generally reported for endemic plants. Populations were well differentiated, with significant clines in allele frequency along the north-south axis of distribution. Pair-wise F-statistics calculated at four levels of population geographic substructure revealed that current and inferred historical habitat patches had similar genetic structure. We found no evidence of recent bottlenecks or changes in genetic structure due to habitat loss and fragmentation, consistent with populations having always …
Monitoring Herpetofauna In A Managed Forest Landscape: Effects Of Habitat Types And Census Techniques, Travis J. Ryan, Thomas Philippi, Yale A. Leiden, Michael E. Dorcas, T. Bently Wigley, J. Whitfield Gibbons
Monitoring Herpetofauna In A Managed Forest Landscape: Effects Of Habitat Types And Census Techniques, Travis J. Ryan, Thomas Philippi, Yale A. Leiden, Michael E. Dorcas, T. Bently Wigley, J. Whitfield Gibbons
Scholarship and Professional Work - LAS
We surveyed the herpetofaunal (amphibian and reptile) communities inhabiting five types of habitat on a managed landscape. We conducted monthly surveys during 1997 in four replicate plots of each habitat type using several different methods of collection. Communities of the two wetland habitats (bottomland wetlands and isolated upland wetlands) were clearly dissimilar from the three terrestrial communities (recent clearcut, pine plantation, and mixed pine–hardwood forest). Among the three terrestrial habitats, the total herpetofaunal communities were dissimilar (P<0.10), although neither faunal constituent group alone (amphibians and squamate reptiles) varied significantly with regard to habitat. Three survey techniques used in the terrestrial habitats were not equally effective in that they resulted in the collection of different subsets of the total herpetofauna. The drift fence technique revealed the presence of more species and individuals in every habitat and was the only one to detect species dissimilarity among habitats. Nonetheless, coverboards contributed to measures of abundance and revealed species not detected by other techniques. We suggest that a combination of census techniques be used when surveying and monitoring herpetofaunal communities in order to maximize the detection of species.
Comparative Genetics Of Seven Plants Endemic To Florida’S Lake Wales Ridge, Eric S. Menges, Rebecca W. Dolan, Rebecca Yahr, Doria R. Gordan
Comparative Genetics Of Seven Plants Endemic To Florida’S Lake Wales Ridge, Eric S. Menges, Rebecca W. Dolan, Rebecca Yahr, Doria R. Gordan
Scholarship and Professional Work - LAS
Here we submit that mathematical tools used in population viability analysis can be used in conjunction with floristic and faunistic surveys to predict changes in biogeographic range. We illustrate our point by summarizing the results of a demographic study of Lobelia boykinii. In this study we used deterministic and stochastic matrix models to estimate the growth rate and to predict the time to extinction for three populations growing in the Carolina bays. The stochastic model better discriminated among the fates of the three populations. It predicted extinction for two populations in the next 25 years but no extinction of the …
Genetic Diversity And Reproductive Biology In Warea Carteri (Brassicaceae), A Narrowly Endemic Florida Scrub Annual, Margaret E.K. Evans, Rebecca W. Dolan, Eric S. Menges, Doria R. Gordon
Genetic Diversity And Reproductive Biology In Warea Carteri (Brassicaceae), A Narrowly Endemic Florida Scrub Annual, Margaret E.K. Evans, Rebecca W. Dolan, Eric S. Menges, Doria R. Gordon
Scholarship and Professional Work - LAS
Carter's mustard (Warea carteri) is an endangered, fire-stimulated annual endemic of the Lake Wales Ridge, Florida, USA. This species is characterized by seed banks and large fluctuations in plant numbers, with increases occurring in postdisturbance habitat. We investigated the mating system, patterns of isozyme variation, and effective population sizes of W. carteri to better understand its population biology and to comment on reserve designs and management proposals relevant to this species. Warea carteri is self-compatible and autogamous, and probably largely selfing. Measures of genetic variation in W. carteri were lower than values reported for species with similar ecological …
Conservation Implications Of Genetic Variation In Three Rare Species Endemic To Florida Rosemary Scrub, Rebecca W. Dolan, Rebecca Yahr, Eric S. Menges, Matthew Halfhill
Conservation Implications Of Genetic Variation In Three Rare Species Endemic To Florida Rosemary Scrub, Rebecca W. Dolan, Rebecca Yahr, Eric S. Menges, Matthew Halfhill
Scholarship and Professional Work - LAS
Habitat conversion and fire suppression during the last 50 yr have greatly reduced and altered Florida scrub vegetation, resulting in threats to the persistence of its unique flora. As part of a larger conservation project, we investigated patterns of isozyme variation in three rare perennial scrub plants with overlapping ranges endemic to Florida rosemary scrub on the Lake Wales Ridge. All three species have low levels of genetic variation, comparable to or lower than those generally reported for rare plants with restricted geographic ranges. Liatris ohlingerae has more than twice the expected heterozygosity of the other two species, with little …
The Rare, Serpentine Endemic Streptanthus Morrisonii (Brassicaceae) Species Complex, Revisited Using Isozyme Analysis, Rebecca W. Dolan
The Rare, Serpentine Endemic Streptanthus Morrisonii (Brassicaceae) Species Complex, Revisited Using Isozyme Analysis, Rebecca W. Dolan
Scholarship and Professional Work - LAS
The Streptanthus morrisonii (Brassicaceae) complex is a group of six narrowly-distributed obligate serpentine endemic taxa whose habitat is threatened by geothermal development. Isozyme analysis of this little-studied complex supports the delineation of two species, S. morrisonii and S. brachiatus, but is at odds with the treatment of two subspecies based on morphology. These results may be influenced by small sample sizes but genetic studies of other Streptanthus taxa have shown patterns of relatedness that often transgress subspecies boundaries based on morphology. The present study further shows that members of the S. morrisonii complex share high genetic identity values (mean …
Patterns Of Isozyme Variation In Relation To Population Size, Isolation, And Phytogeographic History In Royal Catchfly, Rebecca W. Dolan
Patterns Of Isozyme Variation In Relation To Population Size, Isolation, And Phytogeographic History In Royal Catchfly, Rebecca W. Dolan
Scholarship and Professional Work - LAS
The distribution of genetic variation within and among plant populations is influenced by both contemporary and historical factors. I used isozyme analysis of band phenotypes to examine genetic structure in the rare prairie forb Silene regia. Relationships between current-day population size, isolation, and phenotypic variation were assessed for 18 populations in two regions with differing postglacial history. Western populations from unglaciated southern Missouri and Arkansas were more genetically diverse based on the Shannon-Weaver index (H) and a polymorphic index than were more eastern populations. These differences may be due to loss of variation with repeated founding of new populations in …
Effects Of A Prescribed Burn On Tree- And Herb-Layer Vegetation In A Post Oak (Quercus Stellata) Dominated Flatwoods, Rebecca W. Dolan
Effects Of A Prescribed Burn On Tree- And Herb-Layer Vegetation In A Post Oak (Quercus Stellata) Dominated Flatwoods, Rebecca W. Dolan
Scholarship and Professional Work - LAS
Post oak flatwoods are an unusual plant community type dominated by even-aged and uniformly sized post oaks (Quercus stellata) growing along level terraces of the Ohio River. Historical evidence exists that fire may play a role in the maintenance of the open canopy and poorly-developed understory characteristic of this community type (Dolan and Menges. 1989). The results of summer vegetation surveys taken yearly from 1989 to 1992 in a post oak flatwoods in southwestern Indiana that was subjected to a prescribed bum in the spring of 1989 are reported in this paper. The objective of the study was to determine …
The Effects Of Seed Size And Maternal Origin On The Distribution Of Individual Plant Size In Ludwigia Leptocarpa (Onagraceae), Rebecca W. Dolan
The Effects Of Seed Size And Maternal Origin On The Distribution Of Individual Plant Size In Ludwigia Leptocarpa (Onagraceae), Rebecca W. Dolan
Scholarship and Professional Work - LAS
Seed size is normally distributed for many annual species, while mature plant size is frequently positively skewed. A study was conducted to determine the influence of seed size and the role of genetic differences in determining relative seedling size for Ludwigia leptocarpa. Seed size had a significant effect on percentage germination and time of seed germination but no effect on dry weight or leaf area of seedlings. Seed size and spacing had a significant effect on seedling dry weight for plants grown under competition, while relative day of emergence had no effect. Familial (genetic) differences were found in average seed …